Ammonium Chloride → ethyl 7-(3,4-difluorobenzyl)-2-(trifluoromethyl)-2H-chromene-3-carboxylate

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Reaction Conditions

Reaction Steps

A solution of Pd(dba)2 (57.5 mg, 0.100 mmole) and tfp (46.7 mg, 0.201 mmole) in anhydrous THF (10.0 mL) was stirred at room temperature for 20 minutes and then cooled to 0° C. Ethyl 7-iodo-2-(trifluoromethyl)-2H-chromene-3-carboxylate prepared as in Example 9a, Step 2 (2.00 g, 5.02 mmole) was added as a solid, followed by a solution of 3,4-difluorobenzyl zinc bromide in anhydrous THF (20.0 mL-0.5 M, 0.100 mmole) added dropwise over 5 minutes. The mixture was stirred at 0° C. for 0.5 h, then at room temperature for 24 h and was then poured into sat. NH4Cl (100 mL) and extracted with EtOAc (2×200 mL). The combined extracts were washed with brine (50 mL), dried over MgSO4, filtered and concentrated in vacuo to give 3.45 g of an orange oil. The crude product was purified by silica chromatography (92.5:7.5 hexanes:EtOAc) to give 1.81 g (91 % yield) of the product as a yellow oil: EIHRMS m/z 398.0955 (M+, C20H15F5O3, Calc'd 398.0941).

Provenance & Evidence